Method for improving and purifying petroleum byproducts



Patented Apr. 18, 1939 UNITED STATES PATENT OFFICE TDOLEUM BYPBODUCTSFrederick E. Frey and Paul A. Bury, Bartlesville, 01th., a-ignors toPhillips Petroleum Company,

Bartlesville, Okla a corporation of Delaware No Drawing. Application May2, 1984. Serial No. 723.607

BOlalms.

This invention relates to methods of treating resinous reaction productsof oleflns and sulfur dioxide for effecting purification and improvingthe moldability by application of heat and pres- 5 sure into coherentforms. Methods of moldin sulfur dioxide-olefin polymers under heat andpressure into coherent bodies have been set forth in a copendingapplication Ser. No. 599,350, filed March 16, 1932.

The object of this invention is severalfold:

1. To produce a molding compound which can be satisfactorily molded intocoherent articles at temperatures and pressures in common use in theplastic molding industry.

2. To produce a molding material substantially free from sulfur dioxideor other compounds which would attack or discolor the tool steelcommonly used for molds and dies.

3. To produce a molding compound which can be transformed by heat andpressure or equivalent methods into transparent or translucent articlesfree from gas bubbles, unreacted hydrocarbons, dirt or other foreignmatter.

4. To produce a molding compound which will remain unchanged underordinary conditions of transporting and storing and will remain sum.-ciently stable during molding so that little offensive or harmful vaporswill be given 01!.

Other objects will be apparent as the disclosure so proceeds.

The process of making these resinous products consists in chemicallyreacting certain oleflnic hydrocarbons, or other olefinic organiccompounds, with sulfur dioxide at moderate temperatures whereby resinousreaction products of high molecular weight are formed.

The methods and conditions for producing these resinous products havebeen set forth in copending applications, Serial Nos. 599,350, fliedMarch 16, 1932, and 628,449, filed August 11, 1932, now Patent No.2,045,592.

After the resin has been formed a more or less complete removal ofunreacted material may then be eifected by distillation or equivalentmeans. but appreciable amounts of sulfur dioxide, other reactants orby-products remain occluded in the resinous product. In the solid formthe resin may be granulated but, owing to the occluded impurities,cannot in many cases be satisfactorily molded 50 under heat and pressurewithout the release of gases or vapors from the resin taking place,whereupon disruptingof the article being molded may result and thesurfaces of the mold be attacked by the gases so released. When evensmall 5 amounts of such impurities are present the molding oftransparent or translucent articles may offer difficulty due to therelease of sulfur dioxide or other impurities and gas bubbles or opaqueareas remain in the molded article, which are obviously undesirable. Forthe removal of such impurities and improving the molding properties ofolefin-sulfur dioxide resins we have in vented new and useful processesas follows:

The crude resin resulting from the reaction of oleflns and sulfurdioxide may be brought into contact with an organic solvent exerting nomore than a limited solvent effect on the resin but capable ofextracting sulfur dioxide, olefins, hydrocarbon polymers, and otherreaction by-products. The extracting liquid is then separatedmechanically from the resin and the small amount of liquid adhering tothe resin is removed by evaporation. Many solvents may be used since itis a peculiarity of these resins that only 9. limited number of solventsexert a strong solvent effect upon the resins. The impurities on theother hand are soluble in most organic solvents. Consequently thesuitability of any particular organic solvent can be ascertained by asimple test. Alcohbls, ketones, ethers, esters, organic chlorides may beused, and many others provided the volatility is sufllciently high toallow of evaporation of virtually the last traces of solvent from theresin at temperatures no higher than 150 to 200 C. within which rangedecomposition of resin will usually begin. We have found methyl alcohol,ethyl alcohol, lsopropyl alcohol, benzene, and acetone particularlysuitable. ln practicing the process, usually the crude resin in granularor powdered form is agitated with a quantity of solvent. The solventdissolves the impurities and is then separated from the resin byfiltration or the equivalent, and the resin is finally dried by heatingin an oven, in vacuo, or in a stream of gas. The extraction step isconveniently conducted at ordinary temperatures but may be carried outat somewhat elevated temperatures if desired, but obviously belowtemperatures at which marked solution or decomposition of resin areapparent. Solvents which soften and swell the resin without dissolvingit may be used for the extraction of impurities and a fine state ofsubdivision of the resin in such cases can usually be dispensed with.

The removal of volatile impurities from the crude resin may also beaccomplished by heat, 50 preferably in a stream of carrying gas orvapor, such as air. steam. or fuel gas which 'serves to sweep awayvolatilized impurities. Any carrying gas or vapor which is substantiallyfree from constituents which react chemically with the resin 55 or whichare strongly adsorbed by it may be used. The higher the temperature themore rapid is the purification: the temperature obviously should notexceed that at which decomposition of the resin itself begins. Theapplication of pressures below atmospheric in the removal of impuritiesin this way facilitates the purification, and we have found heating ofthe impure resin in vacuo at 50-350 0. to effect a purificationsufiicient for many purposes. The purified resin is thus obtained at anelevated temperature, and pressure can be most conveniently applied formolding in some cases without intermediate cooling.

The duration of heating required to effect removal of volatileimpurities is obviously dependent on the characteristics of the resin,the fineness of granulation and the temperature. Usually a period ofheating of two to ten hours is sufficient with a temperature of 100 C.when the resin is granulated to an average particle size of one sixtiethof an inch, and the time period required when heating in vacuo is of thesame order as that required when a stream or gas is passed over theresin. High temperatures and finer subdivision shorten the timerequired, while lower temperatures increase the time. In some cases afinely divided resin may be purified by standing at room temperature ora little above for a period of several days or more with free access ofair or 888.

Although in most cases it is found preferable to treat the resin in afinely divided form by a moderate heating in vacuum or in a stream ofinert carrying gas, it is sometimes desirable to heat the resin to atemperature sufficiently high to make the resin more or less plastic,and mix or knead the resin during the heating with some sort ofmechanical mixing machine. A mixer of the Banbury type provided withsteam heating chambers and having an enclosed mixing chamber which canbe connected to a vacuum pump has been found suitable for suchtreatment. In some cases, a heat treatment by this method of sumcientduration and intensity to decompose a part of the resin may be foundbeneficial in raising the softening temperature of the resin.

We have also found that the duration or intensity of heating required toeffect such purification and produce a resin of satisfactory moldingproperties may be considerably reduced if the resin in granular form ismerely moistened with methyl or ethyl alcohols or acetone, the heatingoperation being applied subsequently in vacuo or in the presence ofgases as described. The reason for the'improvement is not certain, butit is not unlikely that adsorbed impurities are dislodged from theinternal surfaces of the granules, and the evaporation of theimpurities. is facilitated by the presence of solvent undergoingevaporation. Although the reason is not known with certainty,nevertheless, when tensile strength of resins treated by the variousmethods are compared, it is found that treatment comprising moisteningthe resin with an organic liquid, such as methyl alcohol, ethyl alcohol,or acetone, followed by heating to evaporate the organic liquid, eflectsa noticeably greater improvement than does the treatment comprisingheating in vacuo or in a stream of inert gases.

Involatile impurities are not removed by such methods and for theirremoval, extraction by a solvent as previously described is effective;

An example of the first method stated above is as follows: A quantity ofthe dry pulverized resin is placed in a container suitable for tumblingor stirring the contents such as a ball mill or barrel mixer. Methylalcohol is added until a thick slurry is obtained, the exact amountbeing immaterial. The mill is started and mixing continued for one totwo hours after which the slurry is thrown on a filter and the liquidfiltered off. The resin is removed from the filter and slowly dried in awell ventilated even, after which it is ready for molding. The alcoholmay be recovered by distillation.

A specific example of the second method is: A long cylindrical bombbuilt of stainless steel to withstand 100 pounds per square inch vaporpressure is filled with the dry, pulverized resin packed loosely enoughto permit rapid flow of vapors thru it; saturated steam at 80 poundspressure is passed thru the resin for a period of four to six hours;after the bomb has cooled the resin is removed in a condition suitablefor molding.

A specific example of the third method is: The dry, finely-ground resinis heated in a mixer fitted with steam coils or electric heatingelements; heating at a temperature about 30 C. below the softening pointof the resin is continued with stirring for 30 minutes; the resin isthen removed and is ready for use. On account of the high temperaturenecessary to remove S0: effectively by this treatment the resin isslightly darkened in color, therefore one of the first two methods is tobe preferred except in cases where transparency is not of paramountimportance.

An example of the fourth method is: The finely ground resin is mixedwith a sufficient quantity of an organic liquid such as methyl alcoholto wet thoroughly the resin, whereby sulfur dioxide and volatilehydrocarbons are rapidly liberated from the resin as gases; the wetresin is then spread out and dried by careful heating in the atmosphereor in a stream of inert gas. is Having described our invention, what weclaim 1. A process for improving the molding properties, appearance, andmechanical strength of the resinous products of the reaction of sulfurdioxide with olefinic organic bodies, which comprises bringing the saidresinous product into contact with a liquid organic solvent therebyeffecting an extraction of soluble bodies from the resinous product,then mechanically separating the liquid solvent from the resinousproduct, thereafter freeing said product from adhering solvent byevaporation.

2. The process as in claim 8 in which the solvent is selected from thegroup consisting of methyl alcohol, ethyl alcohol, isopropyl alcohol,benzene and acetone.

3. A process for improving the molding properties, and the appearanceand mechanical strength of the molded resinous product of the reactionof sulfur dioxide with an olefinic organic compound, which comprisessubjecting the crude resinous product to an elevated temperature belowthe temperature at which decomposition of the resin begins while passingin contact with said resinous product a stream of inert gas.

4. A process for improving the molding properties, appearance, andmechanical strength of the resinous product of the reaction of sulfurdioxide with olefinlc bodies which comprises moistening the resin in thegranular state with a solvent selected from the group consisting ofmethyl alcoho], ethyl alcohol, isopropyl alcohol, benzene, and acetone,then subjecting the moistened resin to evaporative conditions to eflectremoval of said solvent and volatile nonresinous bodies.

5. In the production oi finished molded articles from crude resinousmasses produwd by the reaction of sulphur dioxide and oleflnlc organiccompounds the step which comprises removing non-resinous impurities fromsaid crude resinone by brlnslng said resinous into contact with a fluidin which non-resinous impurities are dispersed and said resinous are notdispersed at a temperature less than that at which substantialdecomposition of the resinous mass takes place. and removing said fluidand non-resinous impurities dispersed therein.

6. In the production oi iinished molded articles from crude resinousmasses produced by the reaction of sulphur dioxide and oleflnic organiccompounds the step which comprises removing non-resinous impurities fromsaid crude resinous by bringing said resinous masses into contact withan inert gaseous fluid in which volatile non-resinous impurities aredispersed and said resinous masses are not dispersed at a temperatureless than that at which substantialdecompositionottheresinousmsssestakesplaceand removing said inertgaseous iluid and non-resinous impurities therein.

7. In the production or ilnished molded articlestromcruderesinousmassesproducedbythereaction oi sulphur dioxide andoleiinie organic Fimnmucx E.

compounds the step which moistening a granulated crude resinous masswith a volatile organic liquid selected from the group consisting ofmethyl alcohol. ethyl alcohol, iso-propyl alcohol, benzene and acetoneand subsequently removing by evaporation said organic liquid andnon-resinous impurities at a. temperature less than that at whichsubstantial decomposition oi the resinous mass takes place.

8. In the production of finished molded articles from crude resinousmasses produced by the reaction oi sulphur dioxide and oleflnic organiccompounds the step which comprises molstening a granulated cruderesinous mass with a. volatile orghnic liquid selected from the groupconsisting of methyl alcohol, ethyl alcohol, isopropyl alcohol. benzeneand acetone and subsequently removing non-resinous impurities bybringing said moistened resinous masses into contact with an inertgaseous fluid in which volatile non-resinous impurities and saidmoistening liquid are dispersedand said resinousmassisnotdispersed at a.temperature less than that at which substantial decomposition of saidresinmrsmasstakes plaeeandremovingsaid inertgaseousiiuidsnd materialdispersed therein.

FREDERICK ll. FREY. PAUL A. BURY.

April 18, 1939.

FREY, ET AL.

It is herebycertified that error appears in the printed specification ofthe above numbered patent requiring correction as follows: Page 2, sec-0nd column, line 55, for the claim reference numeral "8" read --l--; andthat the said Letters Patent should be read with this correction thereinthat the same may conform to the record of the case in the PatentOffice.

Signed and sealed this sen day of June, A. 12. 191i Seal Henry VanArsdale, Acting Commissioner of Patents;

5. In the production oi finished molded articles from crude resinousmasses produwd by the reaction of sulphur dioxide and oleflnlc organiccompounds the step which comprises removing non-resinous impurities fromsaid crude resinone by brlnslng said resinous into contact with a fluidin which non-resinous impurities are dispersed and said resinous are notdispersed at a temperature less than that at which substantialdecomposition of the resinous mass takes place. and removing said fluidand non-resinous impurities dispersed therein.

6. In the production oi iinished molded articles from crude resinousmasses produced by the reaction of sulphur dioxide and oleflnic organiccompounds the step which comprises removing non-resinous impurities fromsaid crude resinous by bringing said resinous masses into contact withan inert gaseous fluid in which volatile non-resinous impurities aredispersed and said resinous masses are not dispersed at a temperatureless than that at which substantialdecompositionottheresinousmsssestakesplaceand removing said inertgaseous iluid and non-resinous impurities therein.

7. In the production or ilnished molded articlestromcruderesinousmassesproducedbythereaction oi sulphur dioxide andoleiinie organic Fimnmucx E.

compounds the step which moistening a granulated crude resinous masswith a volatile organic liquid selected from the group consisting ofmethyl alcohol. ethyl alcohol, iso-propyl alcohol, benzene and acetoneand subsequently removing by evaporation said organic liquid andnon-resinous impurities at a. temperature less than that at whichsubstantial decomposition oi the resinous mass takes place.

8. In the production of finished molded articles from crude resinousmasses produced by the reaction oi sulphur dioxide and oleflnic organiccompounds the step which comprises molstening a granulated cruderesinous mass with a. volatile orghnic liquid selected from the groupconsisting of methyl alcohol, ethyl alcohol, isopropyl alcohol. benzeneand acetone and subsequently removing non-resinous impurities bybringing said moistened resinous masses into contact with an inertgaseous fluid in which volatile non-resinous impurities and saidmoistening liquid are dispersedand said resinousmassisnotdispersed at a.temperature less than that at which substantial decomposition of saidresinmrsmasstakes plaeeandremovingsaid inertgaseousiiuidsnd materialdispersed therein.

FREDERICK ll. FREY. PAUL A. BURY.

April 18, 1939.

FREY, ET AL.

It is herebycertified that error appears in the printed specification ofthe above numbered patent requiring correction as follows: Page 2, sec-0nd column, line 55, for the claim reference numeral "8" read --l--; andthat the said Letters Patent should be read with this correction thereinthat the same may conform to the record of the case in the PatentOffice.

Signed and sealed this sen day of June, A. 12. 191i Seal Henry VanArsdale, Acting Commissioner of Patents;

